Crystallographically Textured Nanomaterials Produced from the Liquid Phase Sintering of Bi <sub>x</sub>Sb<sub>2- x</sub>Te<sub>3</sub> Nanocrystal Building Blocks.
basic_science · Level V
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- Record sourced from PubMed, PMID 29546994.
- Also identified by DOI 10.1021/acs.nanolett.8b00263.
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Abstract
Bottom-up approaches for producing bulk nanomaterials have traditionally lacked control over the crystallographic alignment of nanograins. This limitation has prevented nanocrystal-based nanomaterials from achieving optimized performances in numerous applications. Here we demonstrate the production of nanostructured Bi <sub>x</sub>Sb<sub>2- x</sub>Te<sub>3</sub> alloys with controlled stoichiometry and crystallographic texture through proper selection of the starting building blocks and the adjustment of the nanocrystal-to-nanomaterial consolidation process. In particular, we hot pressed disk-shaped Bi <sub>x</sub>Sb<sub>2- x</sub>Te<sub>3</sub> nanocrystals and tellurium nanowires using multiple pressure and release steps at a temperature above the tellurium melting point. We explain the formation of the textured nanomaterials though a solution-reprecipitation mechanism under a uniaxial pressure. Additionally, we further demonstrate these alloys to reach unprecedented thermoelectric figures of merit, up to ZT = 1.96 at 420 K, with an average value of ZT<sub>ave</sub> = 1.77 for the record material in the temperature range 320-500 K, thus potentially allowing up to 60% higher energy conversion efficiencies than commercial materials.